Oil fill cap with air/oil separator

ABSTRACT

An oil fill cap for an internal combustion engine replaces a standard cap and provides separation of air and oil in a separation zone within the cap body. The cap body defines a plurality of passages therethrough, including an upstream passage, and first and second downstream passages meeting at a separation junction. The cap body defines a separation zone at the separation junction and receiving the air/oil mixture from the engine through the upstream passage, and sending separated air to the first downstream passage, and sending separated oil to the second downstream passage.

BACKGROUND AND SUMMARY

The invention relates to oil fill caps for internal combustion engines.

The invention provides an oil fill cap for an internal combustionengine, including a cap body having an air/oil separator. The cap ispreferably conveniently mounted to the engine valve cover in place of astandard oil fill cap.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of an oil fill cap constructed in accordancewith the invention.

FIG. 2 is a side elevation view of the cap of FIG. 1.

FIG. 3 is a sectional view of an alternate embodiment of an oil fill capin accordance with the invention.

DETAILED DESCRIPTION

FIGS. 1, 2 show an oil fill cap 20 for an internal combustion engine 22.The cap includes a cap body 24 for mounting to the engine, preferably tovalve cover 25 for receiving an air/oil mixture therefrom as shown atarrow 26. The cap body has a plurality of passages therethrough,including an upstream passage 28 and first and second downstreampassages 30 and 32 meeting at a separation junction 34. The cap bodydefines a separation zone 36 at junction 34 and receiving the air/oilmixture 26 from the engine through upstream passage 28 and sendingseparated air to first downstream passage 30 and sending separated oilto second downstream passage 32. First downstream passage 30 directs theseparated air to a first exit port 38 from the cap body as shown atarrow 40. Second downstream passage 32 directs the separated oil to asecond exit port 42 from the cap body as shown at arrow 44, whichseparated oil is preferably returned to the engine, as shown at dashedreturn tube 46. The separated air may be returned to the air intakesystem of the engine.

In the embodiment of FIG. 1, separation zone 36 is provided by animpaction/separation zone having one or more nozzles 48 acceleratingair/oil mixture 26 against impaction media 50 to separate the air fromthe oil. In another embodiment, the separation zone may additionally oralternatively be provided by a coalescence/separation zone havingcoalescer media, for example as shown in dashed line at 52, coalescinglyseparating the air from the oil.

Cap body 24 is preferably mounted to valve cover 25 in threadedrelation, preferably in the existing threaded oil fill hole 54 in thevalve cover for receiving a standard oil fill cap. Oil fill cap 20replaces a standard oil fill cap, and preferably includes an O-ring seal56 sealing cap 20 in hole 54. To add oil to the engine, return tube 46is slid off exit port 42, and cap 20 is turned counterclockwise toremove same from hole 54, whereafter oil is added through hole 54 in thevalve cover, followed by replacement of cap 20 by clockwise rotation ofsame into threaded hole 54, followed by reconnection of tube 46 to exitport 42. Cap body 24 has a lower hollow tubular neck 58 having an outersurface 60, preferably threaded, engaging valve cover 25 at hole 54, andhaving an inner surface 62 defining upstream passage 28.

FIG. 3 shows an alternate embodiment and uses like reference numeralsfrom above where appropriate to facilitate understanding. FIG. 3 showsan oil fill cap 70 for internal combustion engine 22. The cap has a capbody 72 for preferably mounting to the engine valve cover 25 forreceiving air/oil mixture 26 therefrom. Cap body 72 defines a pluralityof passages therethrough, including an upstream passage 74 and first andsecond downstream passages 76 and 78 meeting at a separation junction80. The cap body defines a separation zone 82 at junction 80 andreceiving air/oil mixture 26 from the engine through upstream passage 74and sending separated air to first downstream passage 76 and sendingseparated oil to second downstream passage 78. First downstream passage76 directs the separated air to a first exit port 84 from the cap bodyas shown at arrow 86. Second downstream passage 78 directs separated oilto a second exit port 88 from the cap body as shown at arrow 90. In theembodiment of FIG. 3, separation zone 82 is provided by animpaction/separation zone having one or more nozzles 92 acceleratingair/oil mixture 26 against impaction media 94 to separate the air fromthe oil. In another embodiment, the separation zone is additionally oralternatively provided by a coalescence/separation zone having coalescermedia such as shown in dashed line at 96 coalescingly separating airfrom oil. In the embodiment of FIG. 4, the separated oil is returned atexit port 88 to passage 74 of the cap body. The separated air at exitport 84 may be supplied to the air intake system of the engine.

Cap body 72, FIG. 3, is preferably mounted to valve cover 25 in threadedrelation, as a replacement for a standard oil fill cap. Cap body 72 hasa lower hollow tubular neck 100 having an outer surface 102, preferablythreaded at 104, engaging valve cover 25 at threaded hole 54, and has aninner surface 106 defining passage 74. Cap body 72 has an upper neck 108provided by a hollow tubular member having inner and outer surfaces 110and 112. Inner surface 110 of upper neck 108 defines a fill passagecommunicating with upstream passage 74 through lower neck 100 to providean oil fill for the engine. Upper neck 108 is closeable by a second cap114. One of the inner and outer surfaces 106 and 102 of lower neck 100and one of the inner and outer surfaces 110 and 112 of upper neck 108are threaded, for thread-mounting to the engine and for thread-mountingto second cap 114, respectively. Preferably, outer surface 102 of lowerneck 100 is threaded, and inner surface 110 of upper neck 108 isthreaded. In FIG. 3, oil is added to the engine by threadingly removingcap 114 from cap body 72 at upper neck 108, and then pouring the oilinto passage 74, while cap body 72 remains attached to engine valvecover 25 during such filling.

In FIG. 1, cap body 24 has an entrance port 116 receiving air/oilmixture 26 from the engine. Upstream passage 28 defines a rectilinearflow path from entrance port 116 to the one or more nozzles 48.Downstream passage 30 has first and second segments 118 and 120.Downstream passage 32 has first and second segments 122 and 124. Firstsegment 118 of downstream passage 30 is common with first segment 122 ofdownstream passage 32. Separated air diverges from separated oil at adivergence junction 126 of the first and second segments 118 and 120 offirst downstream passage 30 and first and second segments 122 and 124 ofsecond downstream passage 32. Second segment 124 of second downstreampassage 32 as it diverges from divergence junction 126 isgravitationally below second segment 118 of first downstream passage 30as it diverges from divergence junction 126. Cap body 24 defines acollection reservoir 128 along second segment 124 of second downstreampassage 32 downstream of divergence junction 126. Second exit 42 fromcap body 24 is an oil drain from collection reservoir 128.

In FIG. 1, second segment 120 of first downstream passage 30 has firstand second sub-portions 130 and 132 in series and passing separated airserially therethrough, namely from first segment 118 of first downstreampassage 30 then through first sub-portion 130 of second segment 120 offirst downstream passage 30 then through second sub-portion 132 ofsecond segment 120 of first downstream passage 30. Air/oil mixture 26flows along a first flow direction 134 through upstream passage 28.Separated air flows along a second flow direction 136 through firstsub-portion 130 of second segment 120 of first downstream passage 30.Separated air flows along a third flow direction 138 through secondsub-portion 132 of second segment 120 of first downstream passage 30.Separated air exits cap body 24 through exit port 38 along secondsub-portion 132 of second segment 120 of first downstream passage 30.The noted first and third flow directions 134 and 138 enter and exit capbody 24, respectively. First and third flow directions 134 and 138 areparallel and opposite to each other. Second flow direction 136 istransverse to first and third flow directions 134 and 138.

In FIG. 3, cap body 72 has an entrance port 150 receiving air/oilmixture 26 from the engine. Upstream passage 74 defines a rectilinearflow path from entrance port 150 to the one or more nozzles 92. Firstdownstream passage 76 has first and second segments 152 and 154. Seconddownstream passage 78 has first and second segments 156 and 158. Firstsegment 152 of first downstream passage 76 is common with first segment156 of second downstream passage 78. Separated air diverges fromseparated oil at a divergence junction 160 of first and second segments152 and 154 of first downstream passage 76 and first and second segments156 and 158 of second downstream passage 78. Second segment 158 ofsecond downstream passage 78 as it diverges from divergence junction 160is gravitationally below second segment 154 of first downstream passage76 as it diverges from divergence junction 160. Cap body 72 defines acollection reservoir 162 along second segment 158 of second downstreampassage 78 downstream of divergence junction 160. Second exit port 88from cap body 72 is an oil drain from collection reservoir 162, to befurther described.

In FIG. 3, common first segments 152 and 156 of first and seconddownstream passages 76 and 78 extend downwardly along a common flowchannel 164 formed between a pair of opposing passage walls 166 and 168in the cap body. Separated air and separated oil flow downwardly throughcommon flow channel 164. Common flow channel 164 has a lower end 170defining the noted divergence junction 160 and at which separated airand separated oil diverge. Separated air flows upwardly as shown at 172along second segment 154 of first downstream passage 76. Separated oilflows downwardly as shown at 174 along second segment 158 of seconddownstream passage 78 to exit port 88.

In FIG. 3, air/oil mixture 26 flows upwardly along a first flowdirection 176 through upstream passage 74. Separated air and separatedoil flow downwardly along a second flow direction 178 through commonflow channel 164. First and second flow directions 176 and 178 areopposite and parallel to each other. Cap body 72 has upper and lowersections 180 and 182. Lower section 182 has the noted wall 166 extendingupwardly and defining upstream passage 74 and providing one of the notedpair of passage walls forming common flow channel 164. Upper section 180of the cap body has the noted wall 168 extending downwardly andconcentrically surrounding wall 166 and defining common flow channel 164therebetween. Wall 168 has a lower end at 170 defining the noteddivergence junction 160 of first and second segments 152 and 154 offirst downstream passage 76 and first and second segments 156 and 158 ofsecond downstream passage 78.

In FIG. 3, second segment 154 of first downstream passage 76 has firstand second sub-portions 184 and 186 in series and passing separated airserially therethrough, namely from first segment 152 of first downstreampassage 76 then through first sub-portion 184 of second segment 154 offirst downstream passage 76 then through second sub-portion 186 ofsecond segment 154 of first downstream passage 76. Air/oil mixture 26flows along first flow direction 176 through upstream passage 74.Separated air then flows along a second flow direction 178 through firstsegment 152 of first downstream passage 76, then the separated air flowsalong a third flow direction 188 through first sub-portion 184 of secondsegment 154 of first downstream passage 76, then the separated air flowsalong a fourth flow direction 190 through second sub-portion 186 ofsecond segment 154 of first downstream passage 76. The separated airexits cap body 72 through exit port 84 along second sub-portion 186 ofsecond segment 154 of first downstream passage 76. First and third flowdirections 176 and 188 are in the same direction and parallel to eachother. Second flow direction 178 is opposite and parallel to flowdirections 176 and 188. Flow direction 190 is transverse to flowdirections 176, 178, 188.

In FIG. 3, a baffle 192 is provided in the cap body along second segment158 of second downstream passage 78 and downstream of divergencejunction 160 and upstream of collection reservoir 162 and directingseparated oil to flow into collection reservoir 162. Collectionreservoir 162 is gravitationally spaced below divergence junction 160 bya vertical gap 194. Baffle 192 spans laterally in gap 194 to dampensurges of oil in collection reservoir 162 towards divergence junction160. Second segment 158 of second downstream passage 78 includes a checkvalve passage 196 between collection reservoir 162 and exit port 88. Aone-way check valve 198 in check valve passage 196 permits oil drainflow from collection reservoir 162 to exit port 88, and blocks reverseflow from exit port 88 to collection reservoir 162. In this embodiment,oil drains from the collection reservoir back to the engine through exitdrain port 88 into passage 74 when the engine is off and when there issufficient liquid head volume in collection reservoir 162 to open checkvalve 198. The volume of collection reservoir 162 is selected to holdenough separated oil during running of the engine until the nextshut-off, e.g. typically not more than eight hours, though the reservoir162 can be sized according to need. In a further alternative, an oildrain tube may be provided from exit port 88 and/or reservoir 162 andextend downwardly through passage 74 into the engine valve cover if itdoes not interfere with components therein, such as reciprocating valvestems, rocker arms, etc.

In the foregoing description, certain terms have been used for brevity,clearness, and understanding. No unnecessary limitations are to beimplied therefrom beyond the requirement of the prior art because suchterms are used for descriptive purposes and are intended to be broadlyconstrued. The different configurations, systems, and method stepsdescribed herein may be used alone or in combination with otherconfigurations, systems and method steps. It is to be expected thatvarious equivalents, alternatives and modifications are possible withinthe scope of the appended claims.

1. An oil fill cap for an internal combustion engine, said capcomprising a cap body for mounting to said engine for receiving anair/oil mixture therefrom, said cap body defining a plurality ofpassages therethrough, including an upstream passage and first andsecond downstream passages meeting at a separation junction, said capbody defining a separation zone at said separation junction andreceiving said air/oil mixture from said engine through said upstreampassage and sending separated air to said first downstream passage andsending separated oil to said second downstream passage, said firstdownstream passage directing said separated air to a first exit portfrom said cap body, said second downstream passage directing saidseparated oil to a second exit port from said cap body, wherein fill oilpasses into said upstream passage without passing through saidseparation zone, and wherein said fill oil flows into said upstreampassage in the opposite direction of flow of said air/oil mixture insaid upstream passage, wherein said cap body has upper and lower necks,said lower neck being a hollow tubular member having inner and outersurfaces, said inner surface defining said upstream passage, said upperneck being a hollow tubular member having inner and outer surfaces, saidinner surface of said upper neck defining a fill passage communicatingwith said upstream passage through said lower neck to provide an oilfill for said engine, said upper neck being closeable by a second cap,said fill passage communicating with said upstream passage withoutpassing through said separation zone, said fill passage supplying saidfill oil to said upstream passage in the opposite flow direction of saidair/oil mixture in said upstream passage, wherein one of said inner andouter surfaces of said lower neck and one of said inner and outersurfaces of said upper neck are threaded, said lower neck beingthread-mounted to said engine, said upper neck being thread-mounted tosaid second cap, wherein said outer surface of said lower neck and saidinner surface of said upper neck are threaded.
 2. An oil fill cap for aninternal combustion engine, said cap comprising a cap body for mountingto said engine for receiving an air/oil mixture therefrom, said cap bodydefining a plurality of passages therethrough, including an upstreampassage and first and second downstream passages meeting at a separationjunction, said cap body defining a separation zone at said separationjunction and receiving said air/oil mixture from said engine throughsaid upstream passage and sending separated air to said first downstreampassage and sending separated oil to said second downstream passage,said first downstream passage directing said separated air to a firstexit port from said cap body, said second downstream passage directingsaid separated oil to a second exit port from said cap body, whereinfill oil passes into said upstream passage without passing through saidseparation zone, and wherein said fill oil flows into said upstreampassage in the opposite direction of flow of said air/oil mixture insaid upstream passage, wherein said separation zone comprises animpaction/separation zone comprising one or more nozzles acceleratingsaid air/oil mixture against impaction media to separate said air fromsaid oil, wherein each of said first and second downstream passages hasfirst and second segments, said first segment of said first downstreampassage being common with said first segment of said second downstreampassage, said separated air diverging from said separated oil at adivergence junction of said first and second segments of said firstdownstream passage and said first and second segments of said seconddownstream passage, wherein said second segment of said seconddownstream passage as said second segment of said second downstreampassage diverges from said divergence junction is gravitationally belowsaid second segment of said first downstream passage as said secondsegment of said first downstream passage diverges from said divergencejunction, wherein said cap body defines a collection reservoir alongsaid second segment of said second downstream passage downstream of saiddivergence junction, and wherein said second exit port from said capbody is an oil drain from said collection reservoir, and comprising abaffle in said cap body along said second segment of said seconddownstream passage and downstream of said divergence junction andupstream of said collection reservoir and directing said separated oilto flow into said collection reservoir.
 3. The oil fill cap according toclaim 2 wherein said collection reservoir is gravitationally spacedbelow said divergence junction by a vertical gap, and said baffle spanslaterally in said gap to dampen surges of oil in said collectionreservoir towards said divergence junction.
 4. An oil fill cap for aninternal combustion engine, said cap comprising a cap body for mountingto said engine for receiving an air/oil mixture therefrom, said cap bodydefining a plurality of passages therethrough, including an upstreampassage and first and second downstream passages meeting at a separationjunction, said cap body defining a separation zone at said separationjunction and receiving said air/oil mixture from said engine throughsaid upstream passage and sending separated air to said first downstreampassage and sending separated oil to said second downstream passage,said first downstream passage directing said separated air to a firstexit port from said cap body, said second downstream passage directingsaid separated oil to a second exit port from said cap body, whereinfill oil passes into said upstream passage without passing through saidseparation zone, and wherein said fill oil flows into said upstreampassage in the opposite direction of flow of said air/oil mixture insaid upstream passage, wherein said separation zone comprises animpaction/separation zone comprising one or more nozzles acceleratingsaid air/oil mixture against impaction media to separate said air fromsaid oil, wherein each of said first and second downstream passages hasfirst and second segments, said first segment of said first downstreampassage being common with said first segment of said second downstreampassage, said separated air diverging from said separated oil at adivergence junction of said first and second segments of said firstdownstream passage and said first and second segments of said seconddownstream passage, wherein said second segment of said seconddownstream passage as said second segment of said second downstreampassage diverges from said divergence junction is gravitationally belowsaid second segment of said first downstream passage as said secondsegment of said first downstream passage diverges from said divergencejunction, wherein said cap body defines a collection reservoir alongsaid second segment of said second downstream passage downstream of saiddivergence junction, and wherein said second exit port from said capbody is an oil drain from said collection reservoir, wherein said secondsegment of said second downstream passage includes a drain passagebetween said collection reservoir and said second exit port, andcomprising a one-way check valve in said drain passage permitting oildrain flow from said collection reservoir to said second exit port andblocking reverse flow from said second exit port to said collectionreservoir.
 5. The oil fill cap according to claim 4 wherein said secondexit port drains said separated oil to said upstream passage in said capbody.